Railway switch controlling apparatus



Nov. 6, 1956 E. DODD RAILWAY SWITCH CONTROLLINGAPPARATUS 2 Sheets-Sheet1 Filed June 16, 1951 INVENTOR. Arthur E. Dodd 15 ATTORNEY Nov. 6, 1956A. DODD RAILWAY SWITCH CONTROLLING APPARATUS 2 Sheets-Sheet 2 Filed Junel6,- 1951 MEIE United States Patent RAILWAY SWITCH CONTROLLING APPARATUSArthur E. Dodd, Edgewood, Pa., assignor to Westinghouse Air BrakeCompany, a corporation of Pennsylvania Application June 16, 1951, SerialNo. 231,977

Claims. (Cl. 246-219) My invention relates to railway switch controllingapparatus. More particlularly, my invention relates to control apparatusfor manually efi'ecting operation of a railway track switch from aremote point.

Railway switch operating mechanisms 'of the wellknown electropneumatictype are equipped with control elements designated as normal, reverseand lock control magnets. For manually effecting operation of a railwaytrack switch operating mechanism of this type from a remote point, apolarized switch control relay, having a neutral armature and a'polararmature, is commonly employed. Traffic movements over the correspondingswitch are governed by signals for the routes in which the switch isincluded.

A traflic responsive relay such, for example, as a track relayassociated with the switch, is normally energized, but becomesdeenergized in response to a train adjacent the switch, on a route inwhich the switch is included. A switch locking relay is controlled to beenergized, .for closing a front contact, only if the traific responsiverelay is energized, and only if each of the signals which directstraflic movements over the switch is controlled for displaying a stopindication.

It would obviously be unsafe for the switch to be moved from either ofits extreme positions to the other while the associated switch lockingrelay is deenergized, either because of a train adjacent the switch on'a route in which the switch is included, or because a signal iscontrolled for displaying a proceed indication for directing a traflicmovement to be made over the switch. Accordingly, in order to preventmovement of the switch from being manually effected from a remotecontrol point while either of those conditions exists, it has beencommon practice to include a front contact of the switch locking relayin the normal and reverse control circuits for the polarized switchcontrol relay. The polarized switch control relay therefore becomesdeenergized in response to deenergization of the switch locking relay.

For a switch mechanism of the electropneumatic type to move a switch tothe normal position, the normal control magnet and the lock controlmagnet for the switch mechanism must be energized. For such a switchmechanism to move the associated switch to the reverse position, thereverse control magnet and the lock control magnet must be energized.The normal and reverse switch control magnets are commonly energized bycircuits which are controlled by only normal and reverse polar contacts,respectively, of the polarized switch control relay.

The lock control magnet is energized by a circuit which is completedwhen the polar contacts of the polarized switch control relay are movedout of correspondence with the position of the switch, that is, when thepolar contacts of the polarized switch control relay are moved away fromthe normal position while the switch is in the normal position, or whenthe polar contacts of the polarized switch control relay are moved awayfrom the reverse position while the switch is in the reverse position.Therefore, .upon the completition of each operation of the switch to oneof its extreme positions, so that the position of the switch correspondsto the position of the polar contacts of the'polarized switch controlrelay, the lock control magnet will .become deenergized.

The lock control magnet is also controlled by a circuit controlleroperated in conjunction with the switch, so

that the lock control magnet will become energized if the switch shouldbecome misplaced from either of its extreme positions to some pointbetween the two extreme positions. If the polar contacts of thepolarized switch control relay are in the position which corresponds tothe extreme position .of :the switch from which the switch has becomemisplaced, either the normal or the reverse control magnet willtherefore also be energized, while the lock control magnet is energizedbecause of misplacement of :the switch. The switch mechanism will thenact 'to return the switch to the position from which it has beenmisplaced. This method of control is .known as .the restoring featurefor an .electropneumatic switch mechanism.

It follows that, if the restoring feature is to be elfective forrestoring a switch to an extreme position from which it has beenmisplaced while the polarized switch control relay is deenergizedbecause of deenergization of the switch locking relay, the. polarcontacts of the polarized switch control relay must remain closed, whileture in the position which it occupies when the polarized switch controlrelay becames deenergized.

An object of my invention is therefore the provision of a controlarrangement, for an electropneumatic switch mechanism, which :embodies apolarized switch control relay having a polar armature which ismechanically locked in the normal or the reverse position, by a neutralarmature in the deenergized position, while the polarized switch controlrelay is deenergized.

A feature of my invention for accomplishing this ob- V ject is the useof a polarized switch control relay having a neutral armature controlledby biased neutral means with a neutral winding for picking up theneutral armature only when currentof a given polarity is supplied to theneutral winding, and having means controlled by the neutral armature inthe deenergized position for mechanically locking the polar armature ofthe polarized switch control relay in the normal or the reverse positionto which it was last Previously operated in response to energization ofthe relay by current of normal or reverse polarity, respectively.

Another feature of my invention is the provision of a control circuitarrangement embodying only two line control conductors for controlling apolarized switch control relay, of the type in which a polar armature ismechanically locked by a neutral armature in the deenergized condition,for effecting operations of a switch mechanism for moving acorresponding switch to its normal and reverse extreme positions.

If a signal maintainer or other employee shouldremove a polarized switchcontrol relay from the control circuit arrangement for a switch which isprovided with an operating mechanism of the electropneumatic type, forexample, and if the same relay or a similar relay is later Patented Nov.6, 1.95.6

r 3 connected into the switch control circuit arrangement, the polarcontacts of the relay, at the time of being thus connected, may not bein the same position as the polar contacts, of the relay which wasremoved, were occupying at the time of removal of the polarized switchcontrol relay. If, at the time of such reconnection of the con-- trolcircuit arrangement, the switch locking relay were deenergized, thepolarized switch control relay would also remain deenergized, andtherefore the switch might be operated to the wrong position, on accountof the polar contacts of the polarized switch control relay, nowconnected in the control circuit arrangement, being in a differentposition than the polar contacts of the polarized switch control relay,which was removed, were occupying at the time it was removed from theswitch control circuit arrangement.

Another object of my invention is therefore the provision of means forprotecting against operation of a switch to a wrong position, when apolarized switch control relay is removed from a switch control circuitarrangement and is afterwards reconnected in the same switch controlcircuit arrangement or is replaced by a similar relay.

A feature of my invention for accomplishing this object is the provisionof an auxiliary or second neutral armature in addition to the firstneutral armature of the polarized switch control relay, and of means forretaining the auxiliary neutral armature in the picked-up position afterthe relay becomes deenergized, and also of means for rendering theretaining means inefiective, upon either removal of the polarized switchcontrol relay from, or its replacement in, the switch control circuitarrangement, until after the polarized switch control relay has againbeen energized.

Another feature of my invention for accomplishing this object is theprovision of means for opening the control circuit for the polarizedswitch control relay at the time of either removal of the polarizedswitch control relay from or its replacement in the control circuitarrangement for a switch.

Still another feature of my invention is the use of a front contact,operated by the auxiliary or second neutral armature, and a back contactoperated by the first neutral armature, in the control circuits for thenormal and reverse switch control magnets.

I shall describe two forms of apparatus embodying my invention, andshall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a diagrammatic view showingfloneform of apparatus embodying my invention, in which a polarized switchcontrol relay has a neutral armature controlled by a biased neutraldevice embodying a neutral winding for moving the neutral armature to anenergized or picked-up position only while current of a given polarityis supplied to the neutral winding; in which a polar armature of thepolarized switch control relay is mechanically locked, in its normal orits reverse position, by locking mechanism operated by the neutralarmature, when the neutral armature is in a deenergized position; and inwhich the polarized switch control relay is manually controlled from aremote point by a line control circuit arrangement which requires onlytwolinc control conductors.

Fig. 2 is a diagrammatic view showing a modified form of the apparatusof Fig. 1, also embodying my invention, in which a polarized switchcontrol relay embodies, in addition to a first neutral armature, also asecond neutral armature which may be controlled by a first neutralwinding or by a second or auxiliary neutral winding; in which retainingmeans is provided for keeping the second neutral armature in theenergized or picked-up position after the polarized switch control relaybecomes deenergized; in which means. is also provided for rendering theretaining means ineffective for keeping the second neutral armature inthe picked-up position when the switch control relay is either removedfrom or returned to a given location; and in which means is alsoprovided for deenergizing the switch control relay preparatory to itsbeing removed from or returned to the given location.

Referring first to Fig. 1 of the drawings, a railway track switch,designated by the reference character W, is shown in a normal positionin a route over a main track T. An auxiliary track, designated by thereference character t, is connected, by switch W in its reverseposition, with main track T, in a second route.

Tracks T and t are divided by insulated joints 1 to form a switchsection a-b. Section a-b is provided with trafiic responsive means orsafety control means such, for example, as a track relay TR, connectedacross the rails adjacent one end of section ab, and energized bycurrent from a suitable source such, for example, as a battery 2connected across the rails adjacent the opposite end of section a-b.

A signal, designated by the reference character S, is shown forgoverning trafiic movements over a route which includes switch W. SignalS may be of any suitable design such, for example, as the well-knownsearchlight type.

Signal S may be controlled, in any suitable manner, for displaying aproceed indication for directing a traflic movement over a route whichincludes switch W, and therefore for also directing a traffic movementover switch W. As shown in the drawing, the control means for signal Sincludes a manually operable signal control lever SV which may belocated at a remote point such, for example, as an interlocking tower ora dispatchers ofiice. Lever SV has a normal position n, and a controlposition to the left, as shown in the drawing. An energizing circuit fora signal control relay HR is controlled by means including a contact 3,of lever SV, which is closed while lever SV is in its f position. Acircuit for controlling signal S to display a proceed indication iscontrolled by means including a contact 4 of relay HR.

Switch W is operable to a normal position, in which it is shown in thedrawing, or to the opposite or reverse position, by a switch mechanism,designated by the reference character M, which may be of the well-knownelectropneumatic type having normal, reverse and lock control magnets,designated by the reference characters A, R and L, respectively.

A switch circuit controller, designated by the reference character WC,and comprising contacts 5 and 21, is operated in conjunction with switchW. Contact 5 is open while switch W is in either the normal or thereverse extreme position, but is closed while switch W is in anyposition between its normal and reverse extreme positions. Contact 21 isclosed, in the normal position of switch W, in a first control circuitfor controlling a switch indication relay designated by the referencecharacter SS. Contact 21 is also closed, in the reverse position 'ofswitch W, in a second circuit for controlling switch indication relaySS.

Normal and reverse switch control magnets A and R, respectively, forswitch W, are controlled by a polar contact 19, of a polarized switchcontrol relay, designated by the reference character WR, in its normaland reverse positions, respectively.

Lock control magnet L is controlled by a circuit which includes contact5 of switch circuit controller WC, and is also controlled by a branchcircuit which includes contact 6 of switch indication relay SS.

Polarized switch control relay WR embodies a neutral armature bu and apolar armature p. A locking dog 7 is moved to an upper or a lowerposition by a member 8 which is in turn moved up or down by armature bu.In this way, locking dog 7 is moved out of, or into, engagement with alock member 33 which is rigidly attached to armature 1. By this means,polar armature p is locked, in the normal or the reverse position towhich it was last Operated, by neutral armature bu, while relay.WR'isdeenergized.

Qperation of polar armature .p to its normal and .reverse positions iseffected by a polar control winding of relay WR, designated by the.referencecharacter P. Neutral armature bu is controlled by biasedneutral means including a control winding BU of relay WR, so thatarmature bu will be moved to the energized or picked-up position, whencontrol current passes through winding BU in the direction indicatedby'the arrow, and will occupy the deenergized position, in which it isshown in the drawing, when control current passes through winding BU inthe opposite direction, or when no current is passing through windingBU.

A manually operable switch controlling device, shown as alever WV, maybe located in an interlocking tower or a dispatchers oflice. Lever WVhas a normal position 11, in which it is shown in the drawing, and areverse position r.

Current of normal or reverse polarity, according as lever WV is in its11 position or its r position, is supplied over two line controlconductors 14a and 17a of a line control circuit, for energizingwindings BU and P of relay WR. Current for energizing winding P is alsocontrolled by a contact 25, which is controlled by neutral armature bu,and which is closed only while armature bu is in the energized orpicked-up position, and by a contact 15 of a switch locking relay,designated by the reference character LR. Current for energizing windingEU is controlled by polar contacts 16 and 17 of armature p, and bycontact 15 of relay LR, and also by pole-changing contacts of lever WV.

Switch indication relay SS is controlled by a back contact 29 which isclosed while neutral armature bu is in the deenergized position, and isalso controlled by polar contact 22 of polar armature p, as well as bycontact 21 of switch circuit controller WC. Indication means such, forexample, as a lamp E, may be controlled by switch indication relay SS.

Switch locking relay LR is controlled by a front contact of track relayTR, and by a back contact of relay HR. Relay LR is therefore energizedonly while there is no train adjacent switch W on a route whichincludesswitch W, and only while signal S is controlled to display a stopindication. When a train occupies section ab adjacent switch W, or whensignal S for a route which includes switch W is controlled by relay HRto display a proceed indication for directing a trafiic movement overswitch W, relay LR will be deenergized, and therefore the controlcircuits for relay WR will be open at contact 1-5 of relay LR.

Referring now to Fig. 2 of the drawings,the modified form of apparatusembodying my invention, as here shown, embodies all that'is shown inFig. l, including the locking arrangement by means of whichthe neutralarmature bu, controlled by winding BU, locks the polar armature p, whichis controlled by winding P. In order to simplify the drawing, the detailshowing of the locking arrangement is omitted in Fig. 2, but it is to beunderstood that this forms a part of the apparatus of Fig. 2, the sameas it is shown in Fig. l, as indicated by the dash line 32 in Fig. 2.

In addition to the apparatus shown in Fig, l, the modified form ofapparatus embodying my invention, as shown in Fig. 2, includes a secondor auxiliary neutral armature ,1: controlled by means, including a thirdwinding U of relay WR, which is not biased and is therefore responsiveto current of either polarity .for moving armature uto the energized orpicked-up position. A dog 9, pivoted at d, retains armature u in theenergized position when relay WR becomes deenergized.

The base plate of relay WR, designated by the reference character in islocked into a given position or location on a mounting plate at by amanually operable latching device 11, the wedge-shaped lower end ofwhich is forced by a spring g normally into locking engagement with alocking plate 11 which is rigidly connected with mounting plate x. Whilethe lower end 10 of latching device It is in the lock position inlocking plate 11, a contact 27 closes a contact 27a27b which is includedin a control circuit ,for relay WR. Contact 27a-.27b may be insulated,by any suitable means, from spring g, latch h, dog 9, and locking plate11.

When latching device 11 is manually moved upwardly out of lockingengagement with locking plate 11, contact plate 2.7 compresses spring g,opens contact 27a-27b, and rotates dog 9, about the pivot u, out ofengagement with armature u, so that dog 9 is rendered ineffective forretaining armature u in the energized or picked-up position. Armature uwill therefore drop to the deenergized position, and will remain thereuntil winding U again becomes energized. Contacts operated by armature uare included in the control circuits for relay SS and switch controlmagnets A, R and L.

The various circuits shown in the drawings may be supplied withenergizing current from any suitable source such, for example, as abattery Q, shown in Fig. 2, having terminals designated by the referencecharacters B and N.

Having described, in general, the arrangement and control of theapparatus shown by the accompanying drawings, I shall now describe itsoperation in detail.

As shown by the drawings, all parts are in the normal condition, thatis, switch W is in its normal position; signal S is controlled todisplay a stop indication; track section va-b is unoccupied, andtherefore track relay TR is energized; each of the levers SV and WV isin its n position; winding BU is energized by current of normalpolarity, which is opposite to the direction indicated by the arrow, andtherefore armature bu is in the deenergized position, contact 25 ofarmature bu is open, and winding P is deenergized; relay HR, lockcontrol magnet L, and reverse control magnet R are deenergized; relaysSS and LR, normal control magnet A, and indication device E areenergized; and winding U, shown in Fig. 2, is energized.

The circuit by which relay LR is energized passes from terminal B,through contacts 12 and 13 of relays TR and HR, respectively, and thewinding of relay LR to terminal N.

As shown in Fig. 1, current is flowing through winding BU of relay WR,in the direction opposite to the arrow, by a circuit passing fromterminal B, through contact 14 of lever WV, line conductor 14a, contact15 of relay LR, contact 16 of armature p closed in the normal orleft-hand position, winding BU, contact 17 of armature p closed in theleft-hand position, line conductor 17a, and contact 18 of lever WVclosed in the n position, to terminal N.

Switch control magnet A is energized by a circuit passing from terminalB, through contact 19 of armature p closed in the normal or left-handposition, and the winding of magnet A to terminal N.

Relay SS is energized by a circuit passing from terminal B, throughcontact 29 of armature bu, contact 21 of circuit controller WC closed inthe normal position, contact 22 of polar armature p closed in thenormal'position, and the winding of relay SS to terminal N. With relaySS energized, indication lamp E is energized by a circuit passing fromterminal B, through contact 23 of relay SS, and lamp E to terminal N.

In the arrangement shown in Fig. 2, the circuit which is closed forwinding EU is the same as in Fig. 1 except that it includes winding U inseries with winding BU, and includes contact 27a-27b of latching deviceh. Winding U is therefore energized by the current which is passingthrough winding BU in the direction opposite to the arrow. Since windingU is responsive to current of either polarity, its contacts 29, 30 and31 are .closed, and its armature u is inthe loclred-up position. Thecircuit shown in Fig. 2 by Which normal control magnet A is energizedpasses from terminal B, through contact 28 of armature bu, contact 29 ofarmature 11, contact 19 of armature p closed in the normal position, andthe winding of magnet A to terminal N. As shown in Fig. 2, relay SS isenergized by a circuit which is the same as the circuit previouslytraced for relay SS in Fig. 1, except that it includes also contact 30of armature u.

I shall assume that a train moving from right to left, as shown in Fig.1 of the drawings, is to proceed over switch W in the normal position. Aleverman or dispatcher will therefore move lever SV to its 1 position,thereby closing its contact 3 and completing a circuit for energizingrelay HR, this circuit passing from terminal B, through contact 3 oflever SV, and the winding of relay HR to terminal N. With relay HRenergized, a circuit will be completed for controlling signal S todisplay a proceed indication, this circuit passing from terminal B,through contact 4 of relay HR, and the operating mechanism of signal Sto terminal N. Relay HR, upon becoming energized, opens its contact 13,thereby deenergizing relay LR. When relay LR becomes deenergized,contact 15 of relay LR opens the circuit previously traced throughwinding BU of relay WR, and therefore relay WR is now deenergized.

I shall now assume that the train passes signal S onto section a-b,deenergizing relay TR. The circuit for relay LR will therefore now beopened at a second point, on account of contact 12 of relay TR beingopened. Relay LR will therefore remain deenergized as long as eithercontact 12 of relay TR or contact 13 of relay HR is open. Relay WR willin turn remain deenergized as long as relay LR is deenergized. Witharmature bu in the deenergized position, dog 7 is in locking positionwith relation to lock member 33 which is attached to armature p. Thepolar contacts operated by armature p will therefore be locked closed inthe normal position, and normal control magnet A will remain energizedby its circuit previously traced through contact 19 of armature p closedin the normal position.

I shall next assume that the train has left section ab,

and that all parts of the apparatus are again in the normal condition asshown in Fig. 1 of the drawings, and that a leverman then moves lever WVto its r position for reversing switch W. Winding BU of relay WR willnow be energized by current flowing, in the reverse direction indicatedby the arrow, through a circuit passing from terminal B, through contact24 of lever WV closed in the r position, conductor 17a, contact 17 ofarmature p closed in the normal position, winding BU, contact 16 ofarmature p closed in the normal position, contact 15 of relay LR, linecontrol conductor 14a, and contact 26 of lever WV, to terminal N.Armature bu will therefore become raised to the energized position,opening its contact 20, and closing its contact 25.

Contact 20, upon becoming opened, deenergizes relay SS, which, in turn,through its contact 23, deenergizes indication device E. With relay SSdeenergized, lock control magnet L will become energized by a circuitpassing from terminal B, through contact 6 of relay SS, and the windingof lock control magnet L to terminal N.

With contact 25 of armature bu now closed, winding P of relay WR will beenergized by current of reverse polarity passing from terminal B,through contact 24 of lever WV, line conductor 17a, contact 25 ofarmature bu, winding P, contact 15 of relay LR, line conductor 14a, andcontact 26 of lever WV to terminal N. On account of winding P beingenergized by current of reverse polarity, armature p, controlled bywinding P, will move its contacts 16, 17, 19 and 22 to the reverseposition, thereby opening, at contacts 16 and 17, the circuit previouslytraced for winding BU in the direction indicated by the arrow, and alsoopening, at contact 19, the circuit previously traced for normal controlmagnet A.

When contacts 16 and 17 become closed in the reverse position, currentwill flow, in the direction opposite to that indicated by the arrow,through winding BU, by a circuit passing from terminal B, throughcontact 24 of lever WV, line conductor 17a, contact 17 of armature 7closed in the reverse position, winding BU, contact 16 of armature pclosed in the reverse position, contact 15 of relay LR, line conductor14a, and contact 26 of lever WV to terminal N. With winding BU thusenergized by current of polarity opposite to that indicated by thearrow, armature bu will move to the deenergized position, therebyopening its contact 25 in the circuit for winding P, and causing windingP to become deenergized.

With contact 19 of armature 12 now closed in the reverse position,reverse control magnet R will be energized by a circuit passing fromterminal B, through contact 19 of armature p closed in the reverseposition, and the winding of reverse control magnet R to terminal N.With contact 22 of armature p in its reverse position, while contact 21of switch W is in the normal position, relay SS will bedeenergized'although contact 20 of armature bu is now again closed. Lockcontrol magnet L will therefore remain energized by the circuitpreviously traced through contact 6 of relay SS.

With lock control magnet L and reverse control magnet R of mechanism Mboth energized, switch W will now be moved to the reverse position.While switch W is moving between the normal and reverse positions, asecond energizing circuit for lock control magnet L will also be closed,passing from terminal B, through contact 5 of switch circuit controllerWC, and the winding of lock control magnet L to terminal N.

When switch W reaches the reverse position, the circuit for energizingthe winding of lock control magnet L through contact 5 of switch circuitcontroller WC will again be opened. Also, when switch W reaches thereverse position, contact 21 of switch circuit controller WC will beclosed in a second circuit for energizing relay SS, this circuit passingfrom terminal B, through contact 20 of armature bu, contact 21 of switchcircuit controller WC in the reverse position, contact 22 of armature pin the reverse position, and the winding of relay SS to terminal N.

Relay SS, upon becoming energized, will open its contact 6, therebydeenergizing lock control magnet L. With relay SS again energized,indication lamp B will again be energized by its circuit previouslytraced.

I shall now again assume that all parts of the apparatus are returned tothe normal condition and that the leverman again controls signal S todisplay a proceed indication for directing a train to move past signal Sover switch W in the normal position. I shall assume also that, when thetrain passes signal S, and while it is on section a-b, switch W becomesmisplaced.

Lock control magnet L will therefore again be energized by its circuitpreviously traced through contact 5 of switch circuit controller WC.With normal control magnet A energized by its circuit previously tracedthrough contact 19 of armature p closed in the normal osition, and withlock control magnet L energized by the circuit through contact 5 ofswitch circuit controller WC, mechanism M will return switch W to thenormal position.

I shall next assume that, with the arrangement shown in Fig. 2, a signalmaintainer or other employee lifts latch h, preparatory to removingrelay WR from the mounting plate x. Contact plate 27 therefore openscontact 27a27b, causing windings U and BU of relay WR to becomedeenergized. Contact plate 27 also rotates dog 9, around pivot d, out ofengagement with armature u.

With dog 9 out of engagement with armature u, and with winding U ofrelay WR deenergized, armature u will be released to the deenergizedposition. Contacts 29, 30 and 31, operated by armature u, will thereforebe opened.

I shall assume further that the maintainer later returns relay WR orreplaces it by a similar relay. Preparatory to mounting the originalrelay WR or a new relay WR on the plate x, the maintainer will liftlatch h, and will thereby raise contact plate 27, which will in turnmove dog 9 out of engagement with armature u and will open contact27a-27b in the control circuits for relay WR, thus insuring thatarmature u will drop to the deenergized position if it had been lockedup before the original or new relay WR was returned to plate x.

If contacts 16, 17, 19 and 22 of the original or new relay WR are in thenormal position, as shown, when this relay WR is mounted on the plate x,then when the maintainer releases the latch h, permitting contact 27a27bto again be closed, current will again pass through winding BU in thedirection opposite to that indicated by the arrow, and thereforearmature bu of winding BU will remain in the deenergized position.Contact 25 of armature bu will therefore remain open, and winding P willstill be deenergized. With current now flowing through winding U inseries with windning BU, armature u will be raised to its energizedposition, and will be locked there by dog 9. With armature u again inthe energized position, its contact 29 will complete the circuitpreviously traced for normal control magnet A. The circuit forenergizing relay SS will again be completed by contact 35 of relay U.Before relay SS opens its contact 6, lock control magnet L will beenergized for a brief period of time by a circuit passing from terminalB, through contact 6 of relay SS, contact 31 of armature u, and thewinding of lock control magnet L to terminal N. Relay SS, upon becomingenergized, will open its contact 6, and will then again complete thecircuit for lamp E through contact 23 of relay SS.

I shall now assume that all parts-of the apparatus are again in thenormal condition, and that a maintainer again removes relay WR and laterreturns it, or replaces it by a similar relay, but that relay LR isdeenergized because of a train on section ab, and that polar contacts16, 17, 19 and 22 of relay WR are now in the reverse position, out ofcorrespondence with the contacts of lever WV. When the leverman releaseslatch h for again locking relay WR onto mounting plate x, contact 27a27bwill again become closed in the circuit previously described forwindings U and EU of relay WR. With relay LR deenergized, however, itscontact 15 will be open, and therefore relay WR will not becomeenergized, and armature u will remain in the deenergized position. Witharmature u in the deenergized position, its contact 31 will be open, andtherefore lock control magnet L will remain deenergized. Switch W,therefore, cannot be falsely moved to the reverse position on account ofcontact 19 being in the reverse position out of correspondence with thecontacts of lever WV which is in its n position.

When relay LR again becomes energized, windings U and BU will beenergized in series with each other by current flowing in the directionindicated by the arrow in the symbol for winding BU, in a circuitpassing from terminal B, through contact 14 of lever WV, conductor 14a,contact 15 of relay LR, contact 16 of arma ture p closed in the reverseposition, Winding BU, winding U, contact 17 of armature p closed in thereverse posion, contact 27a27b of latch h, conductor 17a, and contact 18of lever WV to terminal N. The contacts operated by armature u will nowbecome closed, but contact 28 of armature bu will be opened, andtherefore reverse control magnet R will not become energized. Witharmature bu in the energized position on account of the energization ofwinding BU by current passing in the direction indicated by the arrow,winding P will be energized by current of normal polarity passing fromterminal B, through contact 14 of lever WV, conductor 14a, contact 15 ofrelay LR, winding P, contact 25 of armature bu, contact 27a27b, linecontrolzconductor 17a, and contact 18 of lever WV to terminal N. Contacts 16, 17, 19 and 22 of armature 12 will therefore be returned to thenormal position. Current will then flow through winding BU in thedirection opposite to the direction indicated by the arrow, andtherefore armature bu will drop to the deenergized position, opening itscontact 25 and closing its contact 28. Normal control magnet A willtherefore again become energized by its circuit previously traced.

It follows that, with the arrangement shown in Fig. 2, if relay WR isremoved from a given location, such for example as on mounting plate x,in which it is connected into the control circuit arrangement for switchW, and if relay WR is later returned, or is replaced by a similar relay,protection is provided against false operation of switch W if the polarcontacts of armature p are out of correspondence with the contacts oflever WV when original relay WR or a new relay is again mounted on platex.

Although I have herein shown and described only two forms of apparatusembodying my invention, it is understood that various changes andmodifications may be made therein Within the scope of the appendedclaims Without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. In combination, a railway track switch, a polarized switch controlrelay mounted in a given location and embodying a polar armature and afirst neutral armature and also a second neutral armature, meanscontrolled by said first neutral armature in a deenergized condition formechanically locking said polar armature in a normal or a reverseposition, biased control means for said first neutral armature forplacing said first neutral armature in an energized condition when saidbiased control means is energized by current of a given reverse polarityand for placing said first neutral armature in a deenergized conditionwhen said biased control means is energized by current of the oppositepolarity or is deenergized, pole-changing means manually operable to anormal or a reverse position, means controlled by said pole-changingmeans in its normal and reverse posi tions for eifecting operation ofsaid polar armature to its normal and reverse positions respectivelyonly if said first neutral armature is in its energized condition,neutral control means for said second neutral armature, means controlledby said pole-changing means and by said polar armature when incorresponding positions for energizing said biased control means andsaid neutral control means by current of said opposite polarity and whenin non-corresponding positions for energizing said biased control meansand said neutral control means by current of said given polarity,retaining means for keeping said second neutral armature in an energizedposition after said switch control relay becomes deenergized in saidgiven location, means rendering said retaining means ineffective to keep.said second neutral armature in the energized position if said switchcontrol relay is removed from said given location, and means controlledby said second neutral aramature in the energized position and by saidpolar armature in its normal and reverse positions for effectingoperation of said switch to normal and reverse positions respectively.

2. In combination, a railway track switch, a polarized switch controlrelay mounted in a given location and embodying a polar armature and afirst neutral armature and also a second neutral armature, meanscontrolled by said first neutral armature in a deenergized condition formechanically locking said polar armature in a normal or a reverseposition, a first and a second control Winding for said first and secondneutral armatures respectively, pole-changing means manually operable toa normal or a reverse position, means controlled by said pole-changingmeans in either its normal or its reverse position for energizing saidsecond neutral control winding for operating said second neutralarmature to an energized position, means controlled by saidpole-changing means in its normal and reverse positions for effectingoperation of said polar armature to its normal and reverse positionsrespectively only if said first neutral armature is in an energizedposition, means controlled by said pole-changing means and by said polararmature in only non-corresponding positions for energizing said firstcontrol Winding for operating said first neutral armature to itsenergized position, retaining means for keeping said second neutralarmature in its energized position while said switch control relay isdeenergized in said given location, means rendering said retaining meansineffective to keep said second neutral armature in the energizedposition if said switch control relay is removed from said givenlocation, and means controlled by said second neutral armature in theenergized position and by said polar armature in its normal and reversepositions for effecting operation of said switch to normal and reversepositions respectively.

3. In combination, a railway track switch, a polarized switch controlrelay mounted in a given location and embodying a polar armature and aneutral armature, pole-changing means operable to a normal and a reverseposition, traific responsive means normally energized but becomingdeenergized in response to a train adjacent said switch on a route inwhich said switch is included, means controlled by said pole-changingmeans in its normal and reverse positions for operating said polararmature to its normal and reverse positions respectively and operatingsaid neutral armature to an energized position only if said trafficresponsive means is energized, retaining means for keeping said neutralarmature in its energized position after said switch control relaybecomes deenergized, means rendering said retaining means ineffective tokeep said neutral armature in the energized position if said switchcontrol relay is removed from said given location, and means controlledby said neutral armature in the energized position and by said polararmature in its normal and reverse positionsfor eifecting operation ofsaid switch to normal and reverse positions respectively.

4..In combination, an electrically controllable device operable to afirst or a second condition, a polarized control relay mounted in agiven location and embodying a polar armature and a neutral armature,pole-changing means operable to a normal and a reverse position, meanscontrolled by said pole-changing means in its normal and reversepositions for operating said polar armature to its normal and reversepositions respectively and operating said neutral armature to anenergized position, retaining means for keeping said neutral armature inits energized position after said polarized control relay becomesdeenergized, means rendering said retaining means inefiective to keepsaid neutral armature in the energized position if said polarizedcontrol relay is removed from said given location, and means controlledby said neutral armature in the energized position and by said polararmature in its normal and reverse positions for effecting operation ofsaid electrically controllable device to said first or second conditionrespectively.

5. In combination, a railway track switch, a polarized switch controlrelay mounted in a given location and embodying a polar armature and aneutral armature, polechanging means operable to a normal and a reverseposition, tratfic responsive means normally energized but becomingdeenergized in response to a train adjacent said switch on a route inwhich said switch is included, means controlled by said pole-changingmeans in its normal and reverse positions for operating said polararmature to its normal and reverse positions respectively and operatingsaid neutral armature to an energized position only if said traflicresponsive means is energized, retaining means for keeping said neutralarmature in its energized position after said switch control relaybecomes deenergized, means for deenergizing said switch control relayand rendering said retaining means ineffective to keep said neutralarmature in the energized position when said switch control relay isremoved from or returned to said given location, and means controlled bysaid neutral armature in the energized position and by said polararmature in its normal and reverse positions for effecting operation ofsaid switch to normal and reverse positions respectively.

References Cited in the file of this patent UNITED STATES PATENTS1,806,817 OHagan May 26, 1931 2,060,485 Bell Nov. 10, 1936 2,082,179OI-Iagan June 1, 1937 2,195,884 Dalzell Apr. 2, 1940 2,491,098 FieldDec. 13, 1949

